Normalising Data

Hi! I have 2 related questions. I hope you can help?

I am building a map that shows spatial growth based on building development between 2005 and 2012.
The 3 attribute fields I am using (along with the other standard ones - Name, Shape, FID etc) include:
1. Completed buildings 2005-2011
2. Completed buildings 2012
3. Suburb area

QUESTION 1
How do I factor in space and number of building developments in order to show spatial intensity of development?
E.g.
a. Suburb 1: 5 developments, 2 square kilometres
b. Suburb 2: 5 developments, 10 square kilometres.
Illustrating this on a map by the number of developments will show these 2 suburbs equally. However, they are very different sizes. Is it possible to factor in the size of the suburb to show the intensity of development within a particular suburb?

QUESTION 2
In order to show the highest growth in the suburbs in 2012, I have normalised "Completed buildings 2012" with "Completed buildings 2005-2011". How do I factor in the size of the suburb in order to illustrate where the highest development is happening in it's spatial componant?

Thanks :)